This project seeks to elucidate the mechanisms by which oral sensory and perceptual experience is generated. Since objective mesurement of the various aspects of oral experience is fundamental to this effort, the selection and refinement of appropriate psychophysical methods is a primary and continuing project concern. Currently, the routine assessment of taste is carried out using aqueous solutions representing each of the four basic tastes. Measures include both (detection) thresholds and judgments of intensity and pleasantness for taste stimuli at higher, more commonly encountered levels of strength. These methods, applied to the study of possible age-associated changes have provided insights into basic mechanisms of chemosensory perception. Functional variation under pathologic circumstances are now being measured. Currently objective evaluations are being made of oral sensory disturbances occurring in association with systemic disease, salivary gland dysfunction or as an isolated complaint. Assessments of olfaction and of oral tactual sensitivity are obtained when they can contribute to an understanding of oral sensory function in relation to the complex stimuli encountered in everyday life.